For a number of years it has been common to manufacture in-the-ear, or in-the-canal hearing aids with a hollow body section, custom designed with an exterior periphery intended to match the curvature of the user's ear canal. The hollow body section usually is bounded on all sides but one. Components such as a receiver are inserted through the open side. The receiver has an audio output port which is usually oriented toward the end of the housing intended to have an audio output port.
The open side is closed with a face plate which usually carries some or all of the remaining necessary components such as a microphone, audio processing circuitry and a power supply such as a battery. The output of the audio processing circuitry is coupled during manufacture to an input port of the receiver.
The face plate is attached to the body section along a laterally directed seam using a variety of mechanical and/or adhesive solutions. Mechanical solutions have included clamps of various types which enable the face plate to grip the open end of the body section. Adhesives have also been used to strengthen the joint.
The above constructions produce a seam that is laterally oriented relative to an axis which extends between the ends. This seam must be mechanically strong enough to resist extraction forces applied to the face plate after the aid has been inserted into the user's ear canal.
The above construction presents manufacturing difficulties. The body section is usually small and is bounded on all sides but the one where the face plate is ultimately attached. Hence, assembling components, such as the receiver or audio processing circuitry into the housing section can be difficult, requiring skill and experience. This results in manufacturing expense and can present reliability problems. In addition, the housing sections are unique as they represent the shape of parts of the user's ear canal, no two of which are the same. This further complicates the assembly process as components are constantly being installed in variably shaped volumes.
There is thus a continuing need for improved hearing aids of a type that extend, at least in part, into the user's ear canal. Preferably manufacturing costs could be reduced while increasing reliability of operation of the completed unit. It would also be preferable if a larger, more open assembly work area could be provided than has heretofore been available. Finally, it would be preferable if an improved joint could be provided between the various parts of the subject hearing aid.